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This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces JT/T 475-2002 Trailer axle. In addition to editorial changes, the following main technical changes have been made with respect to JT/T 475-2002:
——The application scope of the standard is modified, (see Clause 1, Clause 1 of Edition 2002);
——Terms and definitions of trailer axle, rated axle load, wheel track width, suspension center distance, tube body, distance between wheel installation plane, axle body assembly, braking device and hub assembly are added, (see 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8 and 3.9);
——The Clause "Trailer type” is deleted, (see Clause 3 of Edition 2002);
——Basic parameters of trailer axle are modified, (see Clause 4, Clause 4 of Edition 2002);
——Dimension series of tube body section are added, (see 4.2);
——Requirements of paint coating of trailer axle are modified, (see 5.1.3, 5.9 of Edition 2002);
——Requirements of wheel track tolerance of trailer axle are added, (see 5.1.4);
——Interchangeability requirements of trailer axle are added, (see 5.2);
——Requirements of cylindricity error of bearing position are modified, (see 5.3.1.1, 5.3 of Edition 2002);
——Requirements of surface roughness of the axle neck matched with the bearing are modified, (see 5.3.1.3, 5.5 of Edition 2002);
——Requirements of surface roughness of the thread are deleted, (see 5.6 of Edition 2002);
——The tolerance of thread of axle head is modified, (see 5.3.1.4, 5.6 of Edition 2002);
——Requirements of vertical bending stiffness are modified, (see 5.3.2.1, 5.10.1 of Edition 2002);
——Requirements of vertical static bending strength are modified, (see 5.3.2.2, 5.10.2 of Edition 2002);
——Requirements of important components and parts on the trailer axle are added; requirements of the brake lining, brake disc, brake caliper assemble, automatic adjusting arm and camshaft are defined, (see 5.4);
——Requirements of hub assembly are added, (see 5.5);
——The routine inspection method is added, (see 6.1);
——The test method of vertical bending stiffness of axle body assembly is modified, (see 6.2, 6.3 of Edition 2002);
——The wheel track width measurement method is added, (see 6.2.1);
——The test method of vertical static bending strength of axle body assembly is modified, (see 6.3, 6.3 of Edition 2002);
——The test method of vertical bending fatigue life test of axle body assembly is modified, (see 6.4, 6.4 of Edition 2002);
——The test method of camshaft bench test is added, (see 6.6);
——The test method of hub bending fatigue test is added, (see 6.7);
——End-of-manufacturing inspection items, type inspection items and judgment rules are modified; type inspection conditions are added (see Clause 7, Clause 7 of Edition 2002);
——The title of Clause 8 is modified, (see Clause 8, Clause 8 of Edition 2002)
——Contents on the nameplate of product are modified, (see 8.1, 8.1 of Edition 2002).
This standard was proposed by and is under the jurisdiction of Subcommittee on Trailer of National Technical Committee on Automobiles of Standardization Administration of China (SAC/TC 114/SC 13).
The previous editions of this standard are as follows:
——JT/T 3139.1-1989;
——JT/T 3139.2-1989;
——JT/T 475-2002.
Trailer axle
1 Scope
This standard specifies the main technical parameters, technical requirements, test methods, inspection rules, marking and accompanying documents of trailer axle.
It is applicable to road freight trailer axle with rated axle load on a single axle larger than or equal to 1.5t.
2 Normative references
The following referenced documents are indispensable for the application of this standard. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including all amendments) applies.
GB/T 1958 Geometrical Product Specifications (GPS) - Geometrical tolerance - Verification
GB/T 4095 Disc wheels for trucks - Dimensional characteristics of attachment on hub
GB 5763 Brake linings for automobiles
GB/T 15822.1 Non-destructive testing - Magnetic particle testing - Part 1: General principles
GB/T 24607 Rolling bearings - Test and assessment for life and reliability
GB/T 25767 Rolling bearings - Tapered rollers
GB/T 31970 Performance requirements and bench test methods for air brake caliper assemble of automobile
GB/T 34422 Brake disc for automobile
JB/T 5000.3 Heavy mechanical general techniques and standards - Part 3: Weldment
QC/T 239 Specifications and bench test methods for commercial vehicle service brake
QC/T 484-1999 Automobiles - Paint coating
QC/T 1033 Air brake - Performance requirements and bench test methods of external automatic brake adjuster
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
trailer axle
device used to support all or part of the gravity of the trailer and transfer various external forces and reaction forces to ensure the normal driving of the trailer, which mainly includes axle body assembly, braking device and hub assembly
3.2
rated axle load
maximum allowable load that can be borne by the axle as specified by the manufacturer
3.3
wheel track width
TR
distance between the force bearing center points of tyres at both ends of the axle during design, as shown in Figure 1
a) Single-tyre structure b) Double-tyre structure
Figure 1 Wheel track width and suspension center distance
3.4
suspension center distance
B
distance between suspension supporting points, as shown in Figure 1
3.5
tube body
components that can be equipped with relevant components and systems to support all or part of the gravity of the trailer and transmit various external forces and reaction forces to ensure the normal driving of the trailer, as shown in Figure 2
Figure 2 Schematic diagram of tube body
3.6
distance between wheel installation plane
MF
distance between two end faces used to contact the wheel installation plane, located at both ends of the tube body, as shown in Figure 3
Figure 3 Distance between wheel installation plane
3.7
axle body assembly
assembly of relevant parts and components equipped on tube body, used for the installation, fixation and normal use of the braking device, including axle body assembly for drum brake and axle body assembly for disk brake
3.8
axle body assembly for drum brake
combination composed of tube body, brake backing plate, support of brake chamber, support of camshaft etc., as shown in Figure 4
Key:
1——brake backing plate 3——support of brake chamber
2——tube body 4——support of camshaft
Figure 4 Schematic diagram of axle body assembly for drum brake
3.9
axle body assembly for disk brake
combination composed of tube body, brake backing plate, etc., as shown in Figure 5
Key:
1——brake backing plate 2——tube body
Figure 5 Schematic diagram of axle body assembly for disk brake
3.10
braking device
combination of parts and components with the functions of slowing down and stopping the moving parts or machines or maintaining their stopped state, such as commonly used drum brakes and disc brakes
3.11
drum brake
brake with the cylindrical surface as the contact surface of friction pair, consisting of brake drum, brake shoe assembly, camshaft, adjusting arm, etc., as shown in Figure 6
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Main technical parameters
5 Technical requirements
6 Test methods
7 Inspection rules
8 Marking and accompanying documents
